Beam-compass.



PATENTED JAN. 30

A. A. MERRITT. BEAM COMPASS.

APPLICATION FILED JAN.1I,, 1905.

Arron/Wm;

J m/ VENTOI? WITNESSES Specification of Letters Patent.

Patented Jan. 30, 1906.

Application filed January 17,1905. Serial No. 241,462.

T0 at whom it may concern:

Be it known that I, ARTHUR A. MERRITT, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Beam-Compasses, of which the following is a description, reference being had to the accompanying drawings, and to the figures of reference marked thereon.

This invention relates to drawing instruments, and has for .its principal object to pro vide a novel form of beam-compass which may be adjusted with ease and rapidity and. which may be retained in its adjusted position, so that a large number of circles or other marks may be made with the utmost accuracy.

A further object of the invention is to provide a novel form of beam-compass in which the beam is provided with graduations in order to determine the distance between the needle-leg and the marking-leg, the latter term being here used to designate either a pen or pencil.

A still further object of the invention is to provide novel means for adjusting the cl amping of the beam in place, and, further, to so construct the beam and the main orneedle leg that one beam may be readily removed and another of different length or carrying a dif ferent marking means may be substituted therefor.

A still further object of the invention .is to provide means for accurately adjusting the needle-point.

A still further object of the invention is to provide a pen constructioninwhich the blades of the pen maybe firmly held for the purpose of drawing a large number of lines of uniform thickness.

With these and other objects in view, as will more fully hereinafter appear, the invention consists in certain novel features of construction and arrangement of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the form, proportions, size, and minor details of the structure may be made without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawings, Figure 1 is a side elevation of a beam-compass constructed in accordance with the invention. Fig. 2 is an end elevation of the same, the handle being shown in section. Fig. 3 is a transverse sectional elevation of the device on the line 3 3 of Fig. 1. Fig. 4 is a plan view of the instrument. Fig. 5 is a detail sectional view of the needle-carrying leg. Fig. 6 is a sec tional plan view on the line 6 6 of Fig. 7, showing portion of the needle-carrying leg and the beam-clamping disk. Fig. 7 is a transverse sectional elevation of the same on the line 7 7 i of Fig. 6. Fig. 8 is a detail view of the pencil-carrying leg detached.

Similar numerals of reference are employed to indicate corresponding parts throughout the several figures of the drawings.

The main or needle-carrying leg 10 is provided at a point about midway of its length l with. a transvcrsely-disposed slot 11, the side walls of which are arranged on incliped lines, 1 said slot serving for the receptiqn of the beam 12, and the side walls of the latter are also arranged on inclined ii 108, so that when the beam is forced upward it will be firmly clamped in place without contact of the top of the beam with the horizontal wall of the slot. The leg is provided with a threaded portion 13, on which is placed a knurled clamping-nut l4, and said nut serves as a support for a perforated disk 15, having at one edge a verticallyextending lug 16, that fits within a longitudinal groove 17, formed in the bottom of the beam 12, the end wall of the groove being formed by. a downwardly-extended portion 18, Fig. 7, which comes into contact with the lug 16 and prevents accidental removal of the beam. The wall of the opening formed in the disk 15 is extended inwardly to form a lug or key 19, that fits within a correspondinglyshaped groove 20, formed in the periphery of the leg, and. thus prevent independent rotative movement of said disk. WVhen the nut is turned upward, the disk is forced in the same direction and firmly locks the beam in place. By loosening the nut the lug 16 may be removed from the groove and the beam separated from the leg for the substitution of another beam of different length or for a beam carrying a marking'leg of different character.

The side of the beam is provided with gradnations, as indicated in Fig. 1, said graduations being read from the left of the main leg, and the latter being reduced in thickness, as indicated at 22, to facilitate the reading, as will be readily understood on reference to Fig. 4. The leg 10 is provided with a transverse recess 23, in the side walls of which are formed vertical slots 24 for the reception of the end pintles 25 of a worm 26, the latter projecting beyond the opposite sides of the recess in convenient position to be engaged by the fingers of the user, and said worm engages with rack-teeth 27, formed in the upper edge of the beam, so that by turning the worm the downward by a suitable spring 32, that is oonfined in place by a screw 33.

The lower end of the needle-leg 10 is split and is provided with a threaded socket 34 for the reception of a threaded portion of a needle 35, and by turning the needle in the socket the needle-point may be adjusted with the utmost accuracy, this being of especial value to compensate for the rapid wearing away of the pencil-point. When the needle has been adjusted, it may be locked in place in the usual manner by a clampingscrew 36.

One end of the beam is turned to form an approximately U shaped arm 37, having openings for thepassage of securing-screws 38, these screws serving to secure to the beam a marking-leg 39 of the character shown in Fig. 1 or a marking-leg 39 of the character shown in Fig. 8. The marking-le shown in Fig. 1 is of the pen type, and one 0 its blades 40 is rigidly secured in place, while the opposite blade 41 is pivoted at its upper end and is pressed toward the fixed blade by means of a spring 42. The pivoted blade is provided with a threaded opening for the reception of an adjusting-screw 43, and between the head of the screw and the leg is a frictionspring 44 in order to prevent accidental turning oi the screw and the consequent change in the width of the line to be drawn.

The leg 39 (shown in Fig. 8) is provided with a clamping-screw 45, by which a pencilpoint 46 may be locked in place.

With a device of this character it is possible to accurately adjust the distance between the needle-leg and the marking-leg, and the beam may be readily removed when it is desired to substitute a beam of different length or a beam carrying a marking-leg of different character.

In use the clamping-nut 14 is never turned very tight unless it be desired to firmly lock the beam. Under ordinary circumstances the beam will be held under friction, but may be moved by turning the worm, and for rapid adjustment the worm may be lifted out of the rack by upward pressure of the fingers tending and the beam moved freely in either direction.

Having thus described the invention, what is claimed is 1. In a beam-compass, a handled needleleg having a transverse slot, a beam arranged therein and provided with a rack, a looselymounted spring-pressed worm carried by the handle and intermeshing with the rack, the opposite sides of the worm projecting beyond the handle in position to be engaged by the fingers, and a marking leg carried by the beam.

2. In a beam-compass, a handled needleleg having a transverse slot, a beam arranged therein and provided with a rack, a worm engaging the rack and having its opposite sides projecting beyond the handle in position to be engaged by the fingers, and a marking-leg carried by the beam.

3. In a beam-compass, a handled needleleg having two transverse slots, each in a plane at an angle to the other, a beam exthrough one slot and having a rack, a worm extendin through the other slot and intermeshing with the rack, and a markingleg carried by the beam.

4. In a beam-compass, a handled needleleg having two transversely-extending slots each in a plane at an angle to the other, a beam extending through one slot and having a rack, a worm extending through the other slot and intermeshing with the rack, an auxiliary means carried by the leg for locking the beam in adjusted position, and a markingleg carried by the beam.

5. In a device of the class specified, the combination with a transversely-slotted nee dle-leg, of a beam extending through the slot, a marking-leg carried by the beam, a rack on the beam, a worm engaging said rack, said worm being free to move toward and from the beam, and a spring-pressed friction-plate engaging the periphery of the worm, and tending to force the same in the direction of the beam.

6. In a device of the class specified, the combination with a needle-carrying leg having a transverse slot and provided with a handle, a beam adapted to the slot and provided with a rack, a loosely-mounted worm engaging the rack, a spring-pressed pin carried by the handle, a plate arranged at the end of the pin and bearing on the worm, and a markingleg at the end of the beam.

7. In a device of the class specified, a needle-carrying leg having a transverse slot, a beam extending through the slot and provided with a longitudinal groove, a lockingdisk having a lug engaging in the groove, means for preventing independent revoluble movement of the disk, and means for clamping said disk against the bottom of the beam.

8. The combination with a needle-carrying leg having a transverse slot, of a beam arranged inthe slot and provided with a longitudinal groove, a marking-leg at the end of the beam, a disk carried by the leg, and having a lug engaging in said groove, means for preventing independent rotative movement at iihe disk, and a clamping-nut engaging said 9. The combination with a needle-carrying leg having peripheral threads and provided with a keyway, of a beam supported by the leg and having a longitudinal groove in its lower face, a marking-leg at the end of the beam, a disk carried by the leg and having a lug entering the groove, there being a rojecting lug on said disk fitting within the eyway, and a ela1nping-nut mounted on the threaded portion of the leg and engaging said disk.

10. The combination with a needle-earrying leg, of a beam supported thereby and provided on one face with graduations, a marking-leg carried by the beam, a rack on said beam, and a worm engaging the rack, the helideal thread of the worm being also graduate In testimony whereof I affix my signature in presence of two witnesses.

ARTHUR A. MERRITT.

Witnesses:

MILLARD VAN WAGNER, PERLEY T. Srooimnrnenu 

